Body parts for many vehicles are fabricated from several body sheets. Thus far in the automotive industry, these sheets have been mostly made of steel. However, more recently there has been a trend in the automotive industry to replace the heavier steel sheets with lighter aluminum sheets.
In the body fabrication process, aluminum sheets are normally delivered to the stamping line in stacks. In order for the aluminum sheets to proceed into the stamping press, they need to be separated from the stack. However, in the fabrication process, a lubricant is used on the aluminum sheets to prevent damage, oxidation, and etc.
The lubricant, when combined with the lightweight and relatively thin gauge aluminum, promotes a relatively strong viscous hydrodynamic sticking of the sheets. Therefore, it is necessary “to break” this viscous layer to more easily separate the sheets for fabrication. As aluminum sheets need to be fabricated at high speeds, this presents a major problem.
Others in the field have tried to solve the problem of separating lubricated aluminum sheets from one another. For example, U.S. Pat. Nos. 6,468,025 and 4,703,925 disclose apparatuses whereby suction cups attach to a top sheet and pull one or both edges upward. As the edges are pulled upward, a stream of compressed air breaks the adhesion caused by the lubricant. U.S. Pat. No. 5,433,426 discloses another apparatus that uses suction cups to pull one or both edges of a metal sheet upward. As the edges are pulled, they are separated by adjacent horizontal ridges.
In addition to suction cups, mechanical screws, dimples, and brushes have been attempted, but these normally damage the sheet edges.
All of these methods, however, either utilize heavy and complex machinery that are costly to build and maintain or involve undesirable physical alterations to the aluminum sheets.
Thus, it is desirable to develop a unique and cost effective process for separating lubricated aluminum sheets from a stack of aluminum sheets that does not require the use of such machinery or damage the aluminum sheets. In addition, as separating aluminum sheets is a continuing source of downtime, it is desirable to develop a faster separation process.